Transparent micro emulsion

ABSTRACT

A transparent micro-emulsion including two or more nonionic surfactants, two or more oily components, a water-soluble high molecular weight polymer, and a cosmetically acceptable carrier. The sum of the concentration of the surfactants (a) and the oily components (b) is less than about 0.6 wt %. The ratio of the surfactant to the oily component is from about 2:1 to about 1:1.

CONTINUATION DATA

This application is filed under 35 U.S.C. 371, which is the nationalstage of PCT/US99/08233 filed on Apr. 14, 1999.

FIELD

The present invention relates to a transparent micro emulsion. Inparticular, it relates to a transparent micro emulsion for skinmoisturizing, smoothness, and softness.

BACKGROUND

Many personal care products currently available to consumers aredirected primarily to improving the health and/or physical appearance ofthe skin. Among these skin care products, many are directed to delaying,minimizing or even eliminating skin wrinkling and other histologicalchanges typically associated with skin aging or environmental damage tohuman skin such as wrinkling and other forms of roughness (includingincreased pore size, flaking and skin lines). In order to maintain orreturn skin to a healthy and/or youthful state, the skin is typicallytreated with products containing a moisturizing agent. Generally, thegreater the concentration of moisturizing agents the more themoisturization effect to the skin.

Oil-in-water and/or water-in-oil emulsions are well-known. Inparticular, cosmetic products that can be supplied in emulsion forminclude lotions, tonics, serums or toilet waters and also includetransparent and semi-transparent types. Such emulsions, particularlytransparent lotions, are preferable for use in skin care products inorder to provide moistness and softness to the skin, while not causingskin greasiness or stickiness. However, the higher concentration ofmoisturizing agents in such compositions and/or emulsions tends to causethe loss of transparency of the compositions and/or emulsions and mayfurther cause separation of oil and water content as well as sticky andgreasy feeling of skin. The lower the moisturizing agents levels, e.g.,oily components, the lower the moisturizing efficacy to the skin. It isalso known in the arts that certain surfactants are useful foremulsifying oily materials, but increasing the levels in emulsion maycause irritation of skin.

Based on the foregoing, there is a need to seek a transparent emulsionfor improving one's skin condition by maximizing the amount ofmoisturizing agent in the composition and/or improving the spreadabilityof the moisturizing agent to the skin, yet continue to impart anon-greasy feeling to the user.

SUMMARY

The present invention is directed to a transparent micro emulsioncomprising:

(a) two or more nonionic surfactants selected from the group consistingof polyoxyalkylene alkyl ether having the C₁₂₋₁₈ of alkyl substitute,polyoxyalkylene hydrogenated castor oil, and a linear or branched, mono-or tri-alkyl glyceride;

(b) two or more oily components selected from the group consisting ofhydrocarbon oils, fatty acid esters, and silicone oils;

(c) a water-soluble high molecular weight polymer; and

(d) a cosmetically-acceptable carrier comprising a polyol and water.

The sum of the concentration of the surfactants and the oily componentsis less than about 6.0 wt %. The ratio of the surfactants to the oilycomponents is from about 2:1 to about 1:1.

These and other features, aspects, and advantages of the presentinvention will become better understood from a reading of the followingdescription, and appended claims.

DETAILED DESCRIPTION

While the specification concludes with claims particularly pointing outand distinctly claiming the invention, it is believed that the presentinvention will be better understood from the following description.

All percentages, ratios, and levels of ingredients referred to hereinare based on the actually total amount of the composition and/oremulsion, unless otherwise indicated.

All measurements referred to herein are made at 25° C. unless otherwisespecified.

All publications, patent applications, and issued patents mentionedherein are hereby incorporated in their entirety by reference. Citationof any reference is not an admission regarding any determination as toits availability as prior art to the claimed invention.

Herein, “comprising” means that other steps and other ingredients whichdo not affect the end result can be added. This term encompasses theterms “consisting of” and “consisting essentially of.”

Herein, “topical application” means to apply or spread a material ontothe surface of the skin.

Herein, “cosmetically-acceptable carrier,” means one or more compatibledermatologically-acceptable solid or liquid filler diluents orencapsulating substances.

Herein, “dermatologically-acceptable,” means that the compositionsand/or emulsions or components thereof so described are suitable for usein contact with human skin without undue toxicity, incompatibility,instability, irritation allergic response, and the like, commensuratewith a reasonable benefit/risk ratio.

Herein, “safe and effective amount,” means an amount of a compound orcomposition/emulsion sufficient to significantly induce a positivebenefit, preferably a positive skin appearance or feel benefit,including independently the benefits disclosed herein, but low enough toavoid serious side effects, i.e., to provide a reasonable benefit torisk ratio, within the scope of sound judgment of the skilled artisan.

Herein, “mixtures” is meant to include a simple combination of materialsand any compounds that may result from their combination.

All ingredients such as actives and other ingredients useful herein maybe categorized or described by their cosmetic and/or therapeutic benefitor their postulated mode of action. However, it is to be understood thatthe active and other ingredients useful herein can, in some instances,provide more than one cosmetic and/or therapeutic benefit or operate viamore than one mode of action. Therefore, classifications herein are madefor the sake of convenience and are not intended to limit an ingredientto the particularly stated application or applications listed.

A. Transparent Micro Emulsion

The transparent micro emulsion of the present invention includes two ormore nonionic surfactants, two or more oily components, a water-solublehigh molecular weight polymer, and a cosmetically-acceptable carrier.The sum of the concentration of the surfactants (a) and the oilycomponents (b) is less than about 6.0 wt %. The ratio of the surfactantsto the oily components is from about 2:1 to about 1:1. Preferably, thetransparent micro emulsion of the present invention is adermatologically-acceptable topical composition; more preferably acosmetic composition.

Herein, “transparent” means that emulsions have sufficient transparencyto see the other side through the emulsion in a clear glass or plasticbottle. Herein, “micro emulsion” means a solution in which oil andwater, form micelle structures, that are dispersed in solution and suchdispersion is stable over time. Preferably, the droplets present in theemulsions are a mean particle size of less than about 100 mμ meter (0.1μm=100 nm) of; more preferably less than about 80 mμ meter (0.08 μm).Herein, “droplets,” refer to an emulsion particle wherein the water andthe oily component are absorbed together through a surfactant. It isbelieved that the droplets' particle size affect the transparency andturbidity of the emulsion and/or composition which contains oil,surfactants, and water. When the emulsion has droplets which are largein size, particularly more than 0.1 μm, the emulsion tends to be turbid,e.g., not clear. The size of the droplets can be determined using aLaser Scattering Particle Size Distribution Analyzer LA-910 by Horiba(Japan). The size of droplets is measured with the emulsion at atemperature of 25° C.+/−1° C., after 30 seconds mixing.

In another aspect, the transparent micro emulsion of the presentinvention, having the specific combination of more than two surfactantsand oily components has an absorbent value of less than about 2 at awave length of 340 nm; preferably from about 1 to about 1.5 at the samewave length. An emulsion having an absorbent value of greater than 2 atthe above wave length tends to be insufficiently transparent.

The transparent micro emulsion of the present invention, preferably,contains less than 6.0 wt % of the sum of the surfactant (a) and theoily components (b); more preferably less than 3.0 wt %. The ratio ofthe surfactant to the oily component is from about 2:1 to about 1:1.

B. Surfactants

The transparent micro emulsion of the present invention contains two ormore nonionic surfactants selected from the group consisting ofpolyoxyalkylene alkyl ether having the C₁₂₋₁₈ of alkyl substitute,polyoxyalkylene hydrogenerated castor oil, and a liner or branched,mono- or tri-alkyl glyceride. Preferably, at least one of the nonionicsurfactant has a hydrophilic-lipophilic balance (HLB) of more than 10and at least one of the nonionic surfactant has an HLB of less than 10.

Generally, lower HLB components have a larger solubilizing capacity withwater and higher HLB components are effective for mixing with oilycomponents. Without being bound by the theory, it is believed that thelow levels of nonionic surfactant, having low HLB, can be mixed withwater for preparing uniform surfactants-water solution. It is alsobelieved that such mixture can facilitate to mix with oily components,with surfactants having high HLB which are added before the oilycomponents, for preparation of uniform emulsion. Preferably, theemulsion of the present invention contains a large amount of thenonionic surfactants having high HLB than that having low HLB.

Polyoxyalkylene alkyl ether useful herein are the condensation productsof alkylene oxides with both fatty acids and fatty alcohols (e.g.,wherein the polyalkylene oxide portion is esterified on one end with afatty acid and etherified (e.g., connected via an ether linkage) on theother end with a fatty alcohol). These materials have the generalformula R¹CO(X₁)zOR² wherein R¹ and R² are independently alkyl of fromabout 12 to about 18 carbons; X₁ is —OCH₂CH₂ derived from, for exampleethylene glycol or —OCH₂CHCH₃— derived from propylene glycol or oxide;and z is an integer from about 6 to about 50.

Nonlimiting examples of such alkylene oxide derived nonionic surfactantsinclude ceteth-6, ceteth-10, ceteth-12, ceteareth-6, ceteareth-10,ceteareth-12, ceteareth-20, ceteareth-30, steareth-6, steareth-10,steareth-1 2, steareth-20, PEG-100 steareth, PEG-6 stearate, PEG-10stearate, PEG-12 stearate, PEG-100 stearate, PEG-10 glyceryl stearate,PEG-20 glyceryl stearate, PEG-30 glyceryl cocoate, PEG-80 glycerylcocoate, PEG-80 glyceryl tallowate, PEG-200 glyceryl tallowate, PEG-8dilaurate, PEG-10 distearate, and mixtures thereof; preferably,ceteareth-12, ceteareth-20, and ceteareth-30.

Examples of polyoxyalkylene hydrogenerated castor oil useful hereinincludes polyethylene hydrogenerated caster oil; preferably polyethylene(20) hydrogenerated caster oil.

Examples of mono- or tri-alkyl glyceride useful herein includes glycerylmonostearate, glyceryl oleate, and triglyceryl diisostearate; preferablytriglyceryl diisostearate.

Preferably, the total concentration of the nonionic surfactants are fromabout 0.2 wt % to about 2 wt %, preferably from about 0.6% to about 1.2%

C. Oily Component

The transparent micro emulsion of the present invention includes two ormore oily components selected from the group consisting of hydrocarbonoils, fatty acid esters, and silicone oils. The oily components usefulherein provides moisturizing efficacy to the skin.

A wide variety of suitable oil compounds are known and may be usedherein and numerous examples can be found in Sagarin, Cosmetics, Scienceand Technology, 2nd Edition, Vol. 1, pp. 32-43 (1972). Nonlimitingexamples of suitable oily components include C₁₋₃₀ alcohol esters ofC₁₋₃₀ carboxylic acids and of C₂₋₃₀ dicarboxylic acids, hydrocarbonoils, Mono-, di- and tri-glycerides of C₁₋₃₀ carboxylic acids, siliconeoils, mineral oil and petrolatums, vegetable oils and hydrogenatedvegetable oils, animal fats and oils, silicone oils, and mixturethereof; preferably hydrocarbon oils, triglycerides, and silicone oils.Preferred ester include cetyl 2-ethyl hexyl, isopropyl myristate,myristyl myristate, isopropyl palmitate, cholesterol; more preferablycetyl 2-ethyl hexyl and myristyl myristate.

Hydrocarbon oils useful herein includes these having from about 7 toabout 40 carbons. Examples of these hydrocarbon materials includedodecane, isododecane, squalane, hydrogenated polyisobutylene, docosane(i.e., a C₂₂ hydrocarbon), hexadecane, isohexadecane. Also useful arethe C₇₋₄₀ isoparaffins, which are C₇₋₄₀ branched hydrocarbons. Preferredhydrocarbon oils are squalane, light paraffin, light isoparaffin, lightliquid paraffin, light liquid isoparaffin (a commercially availablehydrocarbon sold as Isoper G® by Exxon, Isoparaffin® 2028 by ldemitsu,Amsco Mineral Spirits® by Ashland). Preferred triglycerides includescaprylic/capric triglyceride, PEG-6 caprylic/capric triglyceride, andPEG-8 caprylic/capric triglyceride, Meadowfoam Seed Oil.

Silicone oils useful herein may be volatile, non-volatile, or a mixtureof volatile and non-volatile silicones. The term “nonvolatile” as usedin this context refers to those silicones that are liquid under ambientconditions and have a flash point (under one atmospheric of pressure) ofor greater than about 100° C. The term “volatile” as used in thiscontext refers to all other silicone oils. Suitable silicone oils can beselected from a wide variety of silicones spanning a broad range ofvolatilities and viscosities. Nonvolatile polysiloxanes are preferred.Nonlimiting examples of suitable silicones are disclosed in U.S. Pat.No. 5,069,897, to Orr, issued Dec. 3, 1991, which is incorporated byreference herein in its entirety. Examples of suitable silicone oilsinclude polyalkylsiloxanes, cyclic polyalkylsiloxanes, andpolyalkylarylsiloxanes.

Commercially available polyalkylsiloxanes include thepolydimethylsiloxanes, which are also known as dimethicones, examples ofwhich include the Vicasil® series sold by General Electric Company andthe Dow Corning® 200 series sold by Dow Corning Corporation. Suitabledimethicones include those alkyl-substituted dimethicones include cetyldimethicone and lauryl dimethicone. Commercially available dimethiconolsare typically sold as mixtures with dimethicone or cyclomethicone (e.g.,Dow Corning® 1401 and 1403 fluids). Cyclic polyalkylsiloxanes suitablefor use and commercially available include Dow Corning® 244 fluid, DowCorning® 344 fluid, Dow Corning® 245, and Dow Corning® 345 fluid.

The ratio of the oily components to the surfactants are from about 1:1to about 1:2. Preferably, the oily components are present in aconcentration of less than 3.0 wt % in the emulsion, more preferably,from about 0.5 to about 2.0 wt %.

D. Water-Soluble High Molecular Weight Polymer

The transparent micro emulsions of the present invention include awater-soluble high molecular weight polymer. Preferably, thewater-soluble polymer is present from about 0.0001% to about 0.2% byweight, more preferably from about 0.001% to about 0.1% in the emulsion.

It is believed that a higher level of the water-soluble polymers usefulherein will result in an undesirably tacky or sticky feeling emulsionand a lower level may result in insufficient moisturization andsmoothness of the skin.

Water-soluble polymers useful herein include polysaccharides, gums,mucopolysaccharides (e.g., hyaluronic acid, chondroitin sulfate),carboxylic acid polymers, alkyl acrylate and acric acid copolymer,crosslinked polyacrylate polymers, and mixtures thereof; preferablypolysaccharides, gums, or mixtures thereof.

Extract materials which are derived from natural sources (e.g., QuinceSeed and Sea Weed) can be included as water-soluble polymers. QuinceSeed is available from Taiyo Kagaku (Mie prefecture, Japan). Examples ofsuitable water-soluble polymers for use herein are listed below.

1. Polysaccharide.

A wide variety of polysaccharides can be used in the emulsion of thepresent invention. Herein, “polysaccharides” refers to thickening agentscontaining a backbone of repeating sugar (e.g., carbohydrate) units.Nonlimiting examples of useful polysaccharides include those selectedfrom the group consisting of cellulose, carboxymethylhydroxyethylcellulose, hydroxyethylcellulose, hydroxyethylethylcellulose, hydroxypropylcellulose, hydroxypropyl methylcellulose,methyl hydroxyethylcellulose, microcrystalline cellulose, sodiumcellulose sulfate, pullulan, mannan, tolehalose, and mixtures thereof;more preferably hydroxypropylcellulose.

In the above examples of useful polysaccharides, the hydroxy groups ofthe cellulose polymer are preferably hydroxyalkylated (preferablyhydroxyethylate or hydroxypropylate), forming a hydroxyalkylatedcellulose that is further modified with a straight or branched alkylgroup of from about 10 to about 30 carbons through an ether linkage.Preferred polysaccharides are ethers of straight or branched alcohols offrom about 10 to about 30 carbons with hydroxyalkylcelluloses.

Additional examples of useful polysaccharides include alkyl substitutedcellulose. Nonlimiting examples of the alkyl groups useful hereininclude stearyl, isostearyl, lauryl, myristyl, cetyl, isocetyl, cocoyl(e.g., alkyl groups derived from the alcohols of coconut oil), palmityl,oleyl, linoleyl, linolenyl, ricinoleyl, behenyl, and mixtures thereof.Preferred among the alkyl hydroxyalkyl cellulose ethers herein is thematerial given the CTFA designation cetyl hydroxyethylcellulose, whichis the ether of cetyl alcohol and hydroxyethylcellulose. This materialis sold under the tradename Natrosol® CS Plus from Aqualon Corporation(Willmington, U.S.A.).

Other polysaccharides useful herein include scleroglucans containing alinear chain of (1 to less than 3) linked glucose units with a (1 toless than 6) linked glucose every three units. A commercially availableexample of this is Clearogel™ CS11 from Michel Mercier Products Inc.(Mountainside, N.J., U.S.A.).

2. Gum

Other water-soluble polymers which can be employed in the emulsioninclude materials which are primarily derived from natural sources.Nonlimiting examples of such water-soluble polymers include gumsselected from the group consisting of acacia, agar, algin, alginic acid,ammonium alginate, amylopectin, calcium alginate, calcium carrageenan,camitine, carrageenan, dextrin, gelatin, gellan gum, guar gum, guarhydroxypropyltrimonium chloride, sodium hyaluroinate, hydroxypropylchitosan, hydroxypropyl guar, karaya gum, kelp, locust bean gum, nattogum, potassium alginate, potassium carrageenan, propylene glycolalginate, sclerotium gum, sodium carboxymethyl dextran, sodiumcarrageenan, tragacanth gum, xanthan gum, and mixtures thereof.

Additional polymers which are suitable herein as water-soluble polymersinclude those disclosed in U.S. Pat. No. 4,387,107, to Klein et al.,issued Jun. 7, 1983 and “Encyclopedia of Polymer and Thickeners forCosmetics,” R. Y. Lochhead and W. R. Fron, eds., Cosmetics & Toiletries.vol. 108, pp. 95-135 (May 1993).

D. Cosmetically-Acceptable Carrier

The emulsion of the present invention contains a cosmetically-acceptablecarrier. The carrier used herein can act as a solvent for one or more ofthe other components of the emulsion. Preferably, thecosmetically-acceptable carrier includes a polyol and water. Thecosmetically-acceptable carrier is present from about 80% to about 98.0%in the emulsion; preferable from about 90% to about 95%.

Preferably, the polyols useful herein include, but are not limited to,polyalkylene glycols, more preferably alkylene polyols and theirderivatives including glycerin, propylene glycol, dipropylene glycol,tripropylene glycol, 1.2-pentane diol, polyethylene glycol andderivatives thereof, sorbitol, hydroxypropyl sorbitol, erythritol,threitol, pentaerythritol, xylitol, glucitol, mannitol, hexylene glycol,1,3-butylene glycol, 1,2,6-hexanetriol, glycerol, ethoxylated glycerol,propoxylated glycerol, sodium 2-pyrrolidone-5-carboxylate, solublecollagen, gelatin, 1.2-pentandiol, and mixtures thereof. Preferredpolyols are glycerin, 1,3-butylene glycol, glucose, lactic acid,trimethylglycine, urea, or mixtures thereof; more preferably glycerin or1,3-butylene glycol. The polyols are present in the emulsion from about0.01% to about 20.0%, preferably from about 8.0% to about 15.0%.

The concentration of water in the present emulsion is from about 60 wt %to about 95.0 wt % by weight, preferably from about 80 wt % to about 90wt %. In one embodiment, the carrier can further includes a lower alkylalcohols. The lower alkyl alcohols, if present in the emulsion, areC₁-C₆ alkyl monohydric alcohols; preferably C₂-C₃ alkyl alcohols.Preferred lower alkyl alcohols include ethyl alcohol, isopropyl alcohol,and mixtures thereof.

E. Optional Components

The transparent micro emulsion of the present invention may furthercomprises optional components. Herein, “optional components” means oneor more compatible solid or liquid fillers, diluents, extenders and thelike, which are commonly used in cosmetics as defined herein. The term“compatible” herein means that the components of the emulsions of thisinvention are capable of being commingled with each other, in a mannersuch that there is no interaction which would substantially reduce theefficacy of the emulsion under ordinary use situations.

Optional components useful herein include a pH adjuster and an active.The type of the optional component utilized in the present inventiondepends on the type of the product desired and may comprise severaltypes of carriers including, but not limited to, oil-in-water orwater-in-oil emulsion.

1) pH Adjuster

The optional component can be a pH adjuster. Herein, “pH adjuster”refers to any component which is employed to increase or decrease theoverall pH of the composition/emulsion to an optimum pH, therebypreventing undesirable skin feeling such as skin irritation. An optimumpH is subject to the selection of preventing skin irritation.Preferably, the optimum pH is around 5.0 to about 7.0. Suitable pHadjusters herein include acetate, phosphate, citrate, triethanolamineand carbonate. A combination of the foregoing are often employed toadjust to a specific optimal pH for the composition/emulsion. The totallevel of the pH adjuster is from about 0.01% to about 5.0%, preferably,from about 0.5% to about 2.0%.

2) Actives

The optional component useful herein can also contain actives. Examplesof such actives include, but are not limited to, a vitamin B₃ compound,anti-oxidants and radical scavengers, anti-inflammatory agents,antimicrobial agents, sunscreens and sunblocks, and chelators. Otheractives useful herein include vitamin A (e.g., retinoid which arecommercially available from a number of sources, for example, SigmaChemical Company (St. Louis, Mo.), and Boerhinger Mannheim(Indianapolis, Ind.) and described in U.S. Pat. No. 4,677,120, Parish etal., issued Jun. 30, 1987; U.S. Pat. No. 4,885,311, Parish et al.,issued Dec. 5, 1989; U.S. Pat. No. 5,049,584, Purcell et al., issuedSep. 17, 1991; U.S. Pat. No. 5,124,356, Purcell et al., issued Jun. 23,1992; and Reissue Patent 34,075, Purcell et al., issued Sep. 22, 1992);and vitamin K.

(i) Vitamin B₃ Compounds: The vitamin B₃ compound enhances the skinappearance benefits of the present invention, especially in improvingskin condition, including treating signs of skin aging, more especiallywrinkles, lines, and pores. The vitamin B₃ compound is preferablypresent from about 0.01% to about 50%, more preferably from about 0.1%to about 10%, even more preferably from about 0.5% to about 10%, andstill more preferably from about 1% to about 5%.

Herein, “vitamin B₃ compound” means a compound having the formula:

wherein R is —CONH₂ (e.g., niacinamide), —COOH (e.g., nicotinic acid) or—CH₂OH (e.g., nicotinyl alcohol); derivatives thereof; and salts of anyof the foregoing.

Exemplary derivatives of the foregoing vitamin B₃ compounds includenicotinic acid esters, including non-vasodilating esters of nicotinicacid, nicotinyl amino acids, nicotinyl alcohol esters of carboxylicacids, nicotinic acid N-oxide and niacinamide N-oxide.

Suitable esters of nicotinic acid include nicotinic acid esters of from1 to about 22 carbons, preferably 1 to about 16 carbons, more preferablyalcohols from about 1 to about 6 carbons. The alcohols are suitablystraight-chain or branched chain, cyclic or acyclic, saturated orunsaturated (including aromatic), and substituted or unsubstituted. Theesters are preferably non-vasodilating. As used herein,“non-vasodilating” means that the ester does not commonly yield avisible flushing response after application to the skin in the subjectcompositions/emulsions (the majority of the general population would notexperience a visible flushing response, although such compounds maycause vasodilation not visible to the naked eye, i.e., the ester isnon-rubifacient). Non-vasodilating esters of nicotinic acid includetocopherol nicotinate and inositol hexanicotinate; tocopherol nicotinateis preferred.

Other derivatives of the vitamin B₃ compound are derivatives ofniacinamide resulting from substitution of one or more of the amidegroup hydrogens. Nonlimiting examples of derivatives of niacinamideuseful herein include nicotinyl amino acids, derived, for example, fromthe reaction of an activated nicotinic acid compound (e.g., nicotinicacid azide or nicotinyl chloride) with an amino acid, and nicotinylalcohol esters of organic carboxylic acids (e.g., 1 to about 18carbons). Specific examples of such derivatives include nicotinuric acid(C₈H₈N₂O₃) and nicotinyl hydroxamic acid (C₆H₆N₂O₂), which have thefollowing chemical structures: nicotinuric acid:

nicotinyl hydroxamic acid:

Exemplary nicotinyl alcohol esters include nicotinyl alcohol esters ofthe carboxylic acids salicylic acid, acetic acid, glycolic acid,palmitic acid and the like. Other non-limiting examples of vitamin B₃compounds useful herein are 2-chloronicotinamide, 6-aminonicotinamide,6-methylnicotinamide, n-methyl-nicotinamide, n,n-diethyinicotinamide,n-(hydroxymethyl)-nicotinamide, quinolinic acid imide, nicotinanilide,n-benzylnicotinamide, n-ethylnicotinamide, nifenazone, nicotinaldehyde,isonicotinic acid, methyl isonicotinic acid, thionicotinamide,nialamide, 1-(3-pyridylmethyl) urea, 2-mercaptonicotinic acid, nicomol,and niaprazine.

Nonlimiting examples of the above vitamin B₃ compounds are well known inthe art and are commercially available from a number of sources, e.g.,the Sigma Chemical Company (St. Louis, Mo.); ICN Biomedicals, Inc.(Irvin, Calif.) and Aldrich Chemical Company (Milwaukee, Wis.).

One or more vitamin B3 compounds may be used herein. Preferred vitaminB₃ compounds are niacinamide and tocopherol nicotinate. Niacinamide ismore preferred.

When used, salts, derivatives, and salt derivatives of niacinamide arepreferably those having substantially the same efficacy as niacinamidein the methods of regulating skin condition described herein.

Salts of the vitamin B₃ compound are also useful herein. Nonlimitingexamples of salts of the vitamin B₃ compound useful herein includeorganic or inorganic salts, such as inorganic salts with anionicinorganic species (e.g., chloride, bromide, iodide, carbonate,preferably chloride), and organic carboxylic acid salts (includingmono-, di- and tri-C₁₋₁₈ carboxylic acid salts, e.g., acetate,salicylate, glycolate, lactate, malate, citrate, preferablymonocarboxylic acid salts such as acetate). These and other salts of thevitamin B₃ compound can be readily prepared by the skilled artisan, forexample, as described by W. Wenner, “The Reaction of L-Ascorbic andD-losascorbic Acid with Nicotinic Acid and Its Amide”, J. OrganicChemistry, Vol. 14, 22-26 (1949). Wenner describes the synthesis of theascorbic acid salt of niacinamide.

In a preferred embodiment, the ring nitrogen of the vitamin B₃ compoundis substantially chemically free (e.g., unbound and/or unhindered), orafter delivery to the skin becomes substantially chemically free(“chemically free” is hereinafter alternatively referred to as“uncomplexed”). More preferably, the vitamin B₃ compound is essentiallyuncomplexed. Therefore, if the emulsion contains the vitamin B₃ compoundin a salt or otherwise complexed form, such complex is preferablysubstantially reversible, more preferably essentially reversible, upondelivery of the emulsion to the skin. For example, such complex shouldbe substantially reversible at a pH of from about 5.0 to about 6.0. Suchreversibility can be readily determined by one having ordinary skill inthe art.

More preferably the vitamin B₃ compound is substantially uncomplexed inthe emulsion prior to delivery to the skin. Exemplary approaches tominimizing or preventing the formation of undesirable complexes includeomission of materials which form substantially irreversible or othercomplexes with the vitamin B₃ compound, pH adjustment, ionic strengthadjustment, the use of surfactants, and formulating wherein the vitaminB₃ compound and materials which complex therewith are in differentphases. Such approaches are well within the level of ordinary skill inthe art.

Thus, in a preferred embodiment, the vitamin B₃ compound contains alimited amount of the salt form and is more preferably substantiallyfree of salts of a vitamin B₃ compound. Preferably the vitamin B₃compound contains less than about 50% of such salt, and is morepreferably essentially free of the salt form. The vitamin B₃ compound inthe emulsions hereof having a pH of from about 4 to about 7 typicallycontain less than about 50% of the salt.

The vitamin B₃ compound may be included as the substantially purematerial, or as an extract obtained by suitable physical and/or chemicalisolation from natural (e.g., plant) sources. The vitamin B₃ compound ispreferably substantially pure, more preferably essentially pure.

(ii) Anti-Oxidants and Radical Scavengers: Anti-oxidants and radicalscavengers are especially useful for providing protection against UVradiation which can cause increased scaling or texture changes in thestratum comeum and against other environmental agents which can causeskin damage.

Anti-oxidants and radical scavengers such as tocopherol (vitamin E),tocopherol sorbate, tocopherol acetate, other esters of tocopherol,propyl gallate, alkyl esters of uric acid, amines (i.e.,N,N-diethylhydroxylamine, amino-guanidine), sulfhydryl compounds (i.e.,glutathione), lycine pidolate, arginine pilolate, bioflavonoids, lysine,methionine, proline, superoxide dismutase, silymarin, tea extracts,grape skin/seed extracts, melanin, and rosemary extracts may be used.Preferred anti-oxidants/radical scavengers are selected from tocopherolsorbate and other esters of tocopherol, more preferably tocopherolsorbate. For example, the use of tocopherol sorbate in topical emulsionsand applicable to the present invention is described in U.S. Pat. No.4,847,071, Bissett et al, issued Jul. 11, 1989.

(iii) Anti-Inflammatory Agents: Anti-inflammatory agents enhance theskin appearance benefits, by for example, contribution of uniformity andacceptable skin tone and/or color.

Preferably, the anti-inflammatory agent includes a steroidalanti-inflammatory agent and an non-steroidal anti-inflammatory agent.Preferred steroidal anti-inflammatory for use is hydrocortisone.

The variety of compounds encompassed by this group are well-known tothose skilled in the art. For detailed disclosure of the chemicalstructure, synthesis, side effects, etc. of non-steroidalanti-inflammatory agents, reference may be had to standard texts,including Anti-inflammatory and Anti-Rheumatic Drugs, K. D. Rainsford,Vol. I-III, CRC Press, Boca Raton, (1985), and Anti-inflammatory Agents,Chemistry and Pharmacology, 1, R. A. Scherrer, et al., Academic Press,New York (1974), each incorporated herein by reference.

So-called “natural” anti-inflammatory agents are also useful. Suchagents may suitably be obtained as an extract by suitable physicaland/or chemical isolation from natural sources (i.e., plants, fungi,by-products of microorganisms). For example, alpha bisabolol, aloe vera,Manjistha (extracted from plants in the genus Rubia, particularly RubiaCordifolia), and Guggal (extracted from plants in the genus Commiphora,particularly Commiphora Mukul), kola extract, chamomile, and sea whipextract, may be used.

(iv) Antimicrobial Agent: As used, “antimicrobial agents” means acompound capable of destroying microbes, preventing the development ofmicrobes or preventing the pathogenic action of microbes. Antimicrobalagents are useful, for example, in controlling acne. Preferredantimicrobial agents useful in the present invention are benzoylperoxide, erythromycin, tetracycline, clindamycin, azelaic acid, sulfurresorcinol, phenoxyethanol, and Irgasan™ DP 300 (Ciba Geigy Corp.,U.S.A.). A safe and effective amount of an antimicrobial agent may beadded to emulsions of the present invention, preferably from about0.001% to about 10%, more preferably from about 0.01% to about 5%, stillmore preferably from about 0.05% to about 2%.

(v) Sunscreens and Sunblocks: Sunscreens and sunblocks generally preventexcessive scaling and texture changes of the stratum corneum by exposureof ultraviolet light and may be added to the emulsion of the presentinvention. Suitable sunscreens and sunblocks may be organic orinorganic.

A wide variety of conventional sunscreens and sunblocks are suitable foruse herein. See, U.S. Pat. No. 5,087,445, Haffey et al, issued Feb. 11,1992; U.S. Pat. No. 5,073,372, Turner et al, issued Dec. 17, 1991; U.S.Pat. No. 5,073,371, Turner et al., issued Dec. 17, 1991; and Segarin, etal, at Chapter VIII, pages 189 et seq., of Cosmetics Science andTechnology (1972), which discloses numerous suitable sunscreens andsunblocks. Preferred among those sunscreens and sunblocks which areuseful in the emulsions are those selected from2-ethylhexyl-p-methoxycinnamate (commercially available as PARSOL MCX),butylmethoxydibenzoyl-methane, 2-hydroxy4-methoxybenzo-phenone,2-phenylbenzimidazole-5-sulfonic acid, octyidimethyl-p-aminobenzoicacid, octocrylene, 2-ethylhexyl N,N-dimethyl-p-aminobenzoate,p-aminobenzoic acid, 2-phenylbenzimidazole-5-sulfonic acid, octocrylene,oxybenzone, homomenthyl salicylate, octyl salicylate,4,4′-methoxy-t-butyidibenzoylmethane, 4-isopropyl dibenzoylmethane,3-benzylidene camphor, 3-(4-methylbenzylidene) camphor, titaniumdioxide, zinc oxide, silica, iron oxide, Eusolex™ 6300, Octocrylene,Parsol 1789, and mixtures thereof.

Also particularly useful in the emulsions are sunscreens and sunblockssuch as those disclosed in U.S. Pat. No. 4,937,370, Sabatelli, issuedJun. 26, 1990, and U.S. Pat. No. 4,999,186, Sabatelli, issued Mar. 12,1991. The sunscreens and sunblocks disclosed therein have, in a singlemolecular, two distinct chromophore moieties which exhibit differentultraviolet radiation absorption spectra. One of the chromophoremoieties absorbs predominantly in the UVB radiation range and the otherabsorbs strongly in the UVA radiation range. These sunscreens andsunblocks provide higher efficacy, broader UV absorption, lower skinpenetration and longer lasting efficacy relative to conventionalsunscreens and sunblocks.

Exact amounts will vary depending upon the sunscreen chosen and thedesired Sun Protection Factor (SPF). SPF is a commonly used measure ofphotoprotection of a sunscreen against erythema. See Federal Register,Vol. 43, No. 166, pp. 38206-38269, Aug. 25, 1978.

A sunscreen or sunblock herein may also be added to improve the skin,particularly to enhance their resistance to being washed off by water,or rubbed off. Preferred sunscreens and sunblocks which will providethis benefit are a copolymer of ethylene and acrylic acid. Emulsionscomprising this copolymer are disclosed in U.S. Pat. No. 4,663,157,Brock, issued May 5, 1987.

(vi) Chelators: As used herein, “chelator” refers to a compound thatreacts for removing a metal ion from a system by forming a complex sothat the metal ion cannot readily participate in or catalyze chemicalreactions. The inclusion of a chelator is especially useful forproviding protection against UV radiation which can contribute toexcessive scaling or skin texture changes and against otherenvironmental agents which can cause skin damage.

Exemplary chelators that are useful herein are disclosed in U.S. Pat.No. 5,487,884, Bissett et al, issued Jan. 30, 1996; PCT application91/16035 and 91/16034, Bush et al, published Oct. 31, 1995. Preferredchelators are furildioxime and derivatives thereof.

3) Other Optional Components

In addition to the above described components, the emulsion of thepresent invention may further include preservatives and preservativeenhancers such as water-soluble or solubilizable preservatives includingGermall 115, methyl, ethyl, propyl and butyl esters of hydroxybenzoicacid, benzyl alcohol, EDTA, Bronopol (2-bromo-2-nitropropane-1,3-diol)and phenoxypropanol; antifoaming agents; binders; biological additives;bulking agents; coloring agents; perfumes, essential oils, andsolubilizers thereof; natural extracts; compounds which stimulatecollagen production.

F. Method for Making Composition

The emulsions of the present invention are generally prepared by anymethod conventionally used for providing skin carecompositions/emulsions, particularly for skin lotions and micro emulsionthat are known in the art. Such methods typically involve mixing of theingredients in one or more steps to a relatively uniform state, with orwithout heating, cooling, high share mixing, and the like. Typicalmethods are described in, for example are described in Harry'sCosmeticology, 7th Ed., Harry & Wilkinson (Hill Publishers, London1982).

EXAMPLES

The following examples further describe and demonstrate embodimentswithin the scope of the present invention. The examples are given solelyfor the purpose of illustration and are not to be construed aslimitations of the present invention, as many variations thereof arepossible without departing from the spirit and scope of the invention.Where applicable, ingredients are identified by chemical or CTFA name,or otherwise defined below.

Examples 1-3

Examples 1-3 of the transparent micro emulsion of the present inventionare prepared from the following ingredients by the formulatingtechniques set forth below.

(unit weight %) Phase 1 2 3 A Ceteareth-12¹ 0.02 0.04 0.020 ACeteareth-20² 0.13 0.14 0.054 A Ceteareth-30³ 0.15 0.24 0.097 Atriglyceryl diisostearate 0.32 0.39 0.156 A POE(20) hydrogenated castoroil 0.15 0.12 0.048 A cetyl 2-ethyl hexyl 0.23 0.07 0.028 A meadowfoamseed oil 0.15 0.15 0.060 A benzyl alcohol 0.30 0.30 0.120 B de-water4.30 4.30 1.720 C xanthan gum — — 0.001 C 1,3-butylene glycol 6.40 6.402.560 C glycerine USP 6.00 4.00 2.900 C glyceryl polymethacrylate 4.004.00 1.600 C methylparaben 0.20 0.20 0.080 C sodium benzoate 0.20 0.200.080 C EDTA-2Na 0.10 0.10 0.040 C sodium hydroxide — — 0.070 C alkylacrylate/acrylic acid copolymer — — 0.280 C de-water 76.30 79.35 88.386D dimethyconol and dimethicone — — 1.700 D Merquat Plus 3330⁴ 0.05 — — DPullulan-10% solution 1.00 — — total up to 100 ¹Ceteareth-12:POE(12)Cetostearyl Ether; polyethylene glycol ether of Cetearyl alcoholhaving R(OCH₂CH₂)_(n)OH, n (average) = 12 ²Ceteareth-20:POE(20)Cetostearyl Ether; polyethylene glycol ether of Cettearyl alcoholhaving R(OCH₂CH₂)_(n)OH, n (average) = 20 ³Ceteareth-30:POE(30)Cetostearyl Ether; polyethylene glycol ether of Cettearyl alcoholhaving R(OCH₂CH₂)_(n)OH, n (average) = 30 ⁴Merquat Plus 3330:polyquaternium 39

For Examples 1-3, the cosmetic emulsions are made as follows:

(1) Mix (using propeller type mixer) Phase A ingredients in a suitablysize vessel and heat to about 75-80° C. until the Phase A ingredientsmelt completely.

(2) Add the mixture of Phase A to Phase B and mix at about 75-80° C.

(3) Cool the batch mixture of A-B to about 60° C.

(4) Separately, mix Phase C ingredients at about 70° C. until uniformand cool it about 5° C.

(5) Add Phase C mixture to the batch mixture of phases A-B and mix untiluniform.

(6) Separately, prepare Phase D ingredients until they dissolvecompletely and add to the batch mixture of phases A-C and continue tocool to about 35° C.

(7) Mixing is continued until the resulting batch mixture is uniform.

The embodiments disclosed and represented by the previous examples havemany advantages. For example, the transparent micro emulsion containingspecific combination of the nonionic surfactants and oily components inthe present invention provide maximizing an amount of moisturizingefficacy and skin smoothness and/or improving the spreadability of themoisturizing agent to the skin, yet continue to impart a non-greasyfeeling to the user.

It is understood that the foregoing detailed description of examples andembodiments of the present invention are given merely by way ofillustration, and that numerous modifications and variations may becomeapparent to those skilled in the art without departing from the spiritand scope of the invention; and such apparent modifications andvariations are to be included in the scope of the appended claims.

What is claimed is:
 1. A transparent micro emulsion comprising: (a) twoor more nonionic surfatants selected from the group consisting ofpolyoxyalkylene alkyl ether having the C₁₂₋₁₈ of alkyl substitute,polyoxyalkylene hydrogenated castor oil, and a linear or branched, mono-or tri-alkyl glyceride; (b) two or more oily components selected fromthe group consisting of hydrocarbon oils, fatty acid esters, andsilicone oils; (c) a water soluble high molecular weight polymer; and(d) a cosmetically acceptable carrier comprising a polyol and water,wherein the sum of the concentrations of the surfactants and the oilycomponents is less than about 6.0 wt %; and the ratio of the surfactantsto the oily components is from about 2:1 to about 1:1.
 2. The emulsionof claim 1, wherein at least one of the nonionic surfactants has an HLBof more than 10 and at least one of the nonionic surfactants has an HLBof less than
 10. 3. The emulsion of claim 2, wherein the mean particlesize of the emulsion particles have less than about 100 mμ meter.
 4. Theemulsion of claim 3, wherein the mean particle size of the emulsionparticles have less than about 80 mμ meter.
 5. The emulsion of claim 4,wherein the concentration of the surfactants is from about 0.2% to about2%.
 6. The emulsion of claim 5, wherein the emulsion further comprises apolymer material selected from the group consisting of amphotericpolymers and cationic polymers.
 7. A transparent micro emulsioncomprising: (a) two or more nonionic surfactants selected from the groupconsisting of polyoxyalkylene alkyl ether having the C₁₂₋₁₈ of alkylsubstitute, polyoxyalkylene hydrogenated castor oil, and a linear orbranched, mono- or tri-alkyl glyceride; (b) two or more oily componentsselected from the group consisting of hydrocarbon oils, fatty acidesters, silicone oils, and mixtures thereof; (c) a water-soluble highmolecular weight polymer; and (d) a cosmetically-acceptable carriercomprising a polyol and water, wherein the sum of the concentration ofthe surfactants and the oily components is less than about 6.0 wt %; thetransparent micro emulsion has an absorbance value of less than about 2at a wave length of 340 nm.
 8. The transparent micro emulsion of claim7, wherein the sum of the concentration of the surfactants and the oilycomponents is less than about 3.0 wt %.
 9. The transparent microemulsion of claim 8, wherein the emulsion has an absorbance value offrom about 1.0 to about 1.5 at a wave length of 340 nm.
 10. Thetransparent micro emulsion of claim 9, wherein the concentration of thesurfactants is from about 0.2% to about 1.2 wt % and the ratio of thesurfactant to the oily component is from about 2:1 to about 1:1.